There are a variety of ways to communicate over a channel. Each type of communication channel has advantages and disadvantages and various design tradeoffs. Some systems are more susceptible to dynamic signal distortion than others and some systems have better error detection and/or recovery than others.
Signal isolators can be used to transfer information without a physical connection. For example, optocouplers can include a LED that emits light through an optically transparent insulating film (or dielectric) and strikes a photo detector that generates a current flow that corresponds to the emitted light. RF carriers can also be used to transmit information through a barrier. Data can be transferred from input to output using on/off keying (OOK) or other techniques. Conventional communication channels may have limited channel integrity in signal isolator implementations that restricts their use in certain applications.